President Obama flew home from Europe less than a week ago, and this morning, he is headed back overseas. This time, Air Force One is bound for Africa. It's a weeklong journey that will take the president and his family to three countries covering vastly different regions. This is Obama's first extended trip to the continent as president.

NPR's Ari Shapiro will be on board to cover the trip, and he has this preview.

ARI SHAPIRO, BYLINE: When Barack Obama won his first presidential election, the continent of Africa exploded in jubilation. Jennifer Cooke runs the Africa program at the Center for Strategic and International Studies.

JENNIFER COOKE: Kenya called a national holiday. In Ghana, billboards on the streets. South Africa, people were cheering in the streets when he was elected.

SHAPIRO: Here was the first black president of the United States, a man whose father was born in Kenya. Africans were certain that their continent would become a major priority for the world's largest superpower. In the four years since, many of them have felt disappointed.

MWANGI KIMENYI: When the president came to power, there was too much excitement, and it was misplaced.

SHAPIRO: In the first term, the Obama administration put very little emphasis on Africa. With wars in Iraq and Afghanistan, a global economic crisis and a strategic pivot to Asia, America's international dance card was pretty much full. The president's only visit to sub-Saharan Africa was a quick stop in Ghana, on his way home from Russia and Italy. By the end of this visit, Obama will have added three more African countries to his checklist: Senegal, South Africa and Tanzania.

SHAPIRO: And China's not the only country that's investing heavily in the continent right now. For example, Turkey, Brazil, India, and even Russia have quickly growing footprints in South Africa, says University of Cape Town Professor Haroon Bhorat.

HAROON BHORAT: So you see new emerging markets entering into other emerging markets, like South Africa, and taking advantage of economic opportunities, in a way where the U.S., already with a foothold, arguably hasn't done enough.

SHAPIRO: Here's why all of this matters. When you look at the world's top 10, or even the top 20 fastest-growing economies, half those countries are in Africa. The median age on the continent is 17 years old. So millions of Africans are about to enter the workforce. That could shift the global economic chessboard dramatically.

On the political front, many African strongmen who've held power for decades are gone. There's more democratic stability than there used to be.

And Witney Schneidman says the average African consumer now has buying power that was unheard of a couple decades ago. He handled African affairs at the State Department in the Clinton administration.

WITNEY SCHNEIDMAN: We've seen the emergence of a middle class, some 350 million people that have disposable income. They've got mortgages, cars. They're investing in tuitions, and that's really helping to change the landscape, and I think fuel this growth.

SHAPIRO: Africa also has big new energy reserves that are just coming on the market.

All of those themes are embedded in President Obama's itinerary this week. He has multiple events with youth and with business leaders. In Tanzania, he'll tour a power plant.

There are also some themes on this trip that have been a constant in U.S.-African relations: Obama will hold events on security, health, democracy and rule of law. On Sunday night, he'll deliver the central speech of this trip in Cape Town, South Africa. The message may echo what he said in Ghana four years ago.

(SOUNDBITE OF SPEECH)

PRESIDENT BARACK OBAMA: The 21st century will be shaped by what happens not just in Rome or Moscow or Washington, but by what happens in Accra, as well.

SHAPIRO: The people he'll meet in Senegal, South Africa and Tanzania over the coming week agree with that sentiment. They hope that in President Obama's second term, his actions send the same message as his words.